Plans were unveiled in Russia last month to construct an underground city that could become home to up to 100,000 people. Named Eco-City 2020, it would be constructed inside Siberia’s abandoned Mir diamond mine, which, at a quarter of a mile wide and over 1,700ft deep, is the second largest excavated hole on the planet. The site would be covered completely by a vast glass dome, under which multiple levels would plunder its depth, with natural light piped down through the central core.

“The new city will be divided into three main levels with a vertical farm, forests, residences and recreational areas,” said a spokesperson. “One of the most interesting aspects of the proposal is its glass dome. It will protect the city and be covered by photovoltaic cells that will harvest enough solar energy for the whole development.”